THE USE OF GOLD FOIL WRAPPING FOR RADIATION PROTECTION OF THE SPINAL-CORD FOR RECURRENT TUMOR-THERAPY

Purpose: The development of a technique to provide sufficient radiatio n protection to previously irradiated spinal cord in such a manner tha t interstitial brachytherapy can be conducted after resection of a rec urrent tumor and decompression of the cord. Methods and Materials: A t echnique was developed that uses multiple layers of gold foil that are applied around the thecal sac and nerve root sleeves to produce an en veloping radiation shield after resection of recurrent tumor. Once the layers of gold foil are in place, interstitial I-125 seeds are perman ently placed in the bed of the tumor resection to prevent any recurren ce from microcellular disease. The technique is described and its appl ication in the case of a 28-year-old with a third recurrence of chondr osarcoma after external fractionated radiation therapy at the second t o the fourth thoracic segments is reviewed. Results: This technique ha s been used in this first patient. An additional tumor dose of 120.0 G y was delivered to the tumor bed while the spinal cord was calculated to receive only 1% of the dose over the life span of the implant. To d ate, this dose of radiation has prevented tumor recurrence for more th an 18 months of follow-up. Conclusion: This technique of multiple laye rs of gold foil shielding over the spinal cord and nerve roots has the potential to be a useful toot for the shielding of a previously irrad iated spinal cord in the setting of resection of recurrent tumor. It m ay also have a wider application to a number of other radiosensitive t umors where interstitial brachytherapy may be useful to provide additi onal treatment after external fractionated radiation therapy.